The Critique of Judgement, by Immanuel Kant

Part II

Critique of the Teleological Judgement

§ 61.

Of the objective purposiveness of Nature

We have on transcendental principles good ground to assume a subjective purposiveness in nature, in its particular
laws, in reference to its comprehensibility by human Judgement and to the possibility of the connexion of particular
experiences in a system. This may be expected as possible in many products of nature, which, as if they were devised
quite specially for our Judgement, contain a specific form conformable thereto; which through their manifoldness and
unity serve at once to strengthen and to sustain the mental powers (that come into play in the employment of this
faculty); and to which therefore we give the name of beautiful forms.

But that the things of nature serve one another as means to purposes, and that their possibility is only completely
intelligible through this kind of causality — for this we have absolutely no ground in the universal Idea of nature, as
the complex of the objects of sense. In the above-mentioned case, the representation of things, because it is something
in ourselves, can be quite well thought a priori as suitable and useful for the internally purposive
determination of our cognitive faculties; but that purposes, which neither are our own nor belong to nature (for we do
not regard nature as an intelligent being), could or should constitute a particular kind of causality, at least a quite
special conformity to law — this we have absolutely no a priori reason for presuming. Yet more, experience
itself cannot prove to us the actuality of this; there must then have preceded a rationalising subtlety which only
sportively introduces the concept of purpose into the nature of things, but which does not derive it from Objects or
from their empirical cognition. To this latter it is of more service to make nature comprehensible according to analogy
with the subjective ground of the connexion of our representations, than to cognise it from objective grounds.

Further, objective purposiveness, as a principle of the possibility of things of nature, is so far removed from
necessary connexion with the concept of nature, that it is much oftener precisely that upon which one relies
to prove the contingency of nature and of its form. When, e.g. we adduce the structure of a bird, the
hollowness of its bones, the disposition of its wings for motion and of its tail for steering, etc., we say that all
this is contingent in the highest degree according to the mere nexus effectivus of nature, without calling in
the aid of a particular kind of causality, namely that of purpose (nexus finalis). In other words, nature,
considered as mere mechanism, could have produced its forms in a thousand other ways without stumbling upon the unity
which is in accordance with such a principle. It is not in the concept of nature but quite apart from it that we can
hope to find the least ground a priori for this.

Nevertheless the teleological act of judgement is rightly brought to bear, at least problematically, upon the
investigation of nature; but only in order to bring it under principles of observation and inquiry according to the
analogy with the causality of purpose, without any pretence to explain it thereby. It belongs
therefore to the reflective and not to the determinant judgement. The concept of combinations and forms of nature in
accordance with purposes is then at least one principle more for bringing its phenomena under rules where the
laws of simply mechanical causality do not suffice. For we bring in a teleological ground, where we attribute causality
in respect of an Object to the concept of an Object, as if it were to be found in nature (not in ourselves); or rather
when we represent to ourselves the possibility of the Object after the analogy of that causality which we experience in
ourselves, and consequently think nature technically as through a special faculty. If we did not ascribe to it such a
method of action, its causality would have to be represented as blind mechanism. If, on the contrary, we supply to
nature causes acting designedly, and consequently place at its basis teleology, not merely as a
regulative principle for the mere judging of phenomena, to which nature can be thought as subject in
its particular laws, but as a constitutive principle of the derivation of its products from their
causes; then would the concept of a natural purpose no longer belong to the reflective but to the determinant
Judgement. Then, in fact, it would not belong specially to the Judgement (like the concept of beauty regarded as formal
subjective purposiveness), but as a rational concept it would introduce into natural science a new causality, which we
only borrow from ourselves and ascribe to other beings, without meaning to assume them to be of the same kind with
ourselves.